The Destiny 2 Beta users have discovered a glitch, shortly after the start of the beta, that gives an infinite ammo.
This trick works only in the Strike of the beta. You need a Warlock:
In the course of the story mission the Warlock receives the exotic Sub-machine gun Riskrunner.
This has the Perk Arc Conductor, which is important for the glitch, (if you get Arcade damage, the weapon will be stronger and resist incoming Arc damage) and superconductors (there is a chance that fired shots will return ammo).
In addition, the Warlock has the class ability "Rift". Here is a healing rift with which you create an aura. As long as you stand in this aura, you will be healed.
For the glitch, you only have to place a Healing Rift in the Vex milk (the healing effect is stronger than the damage done by the milk) and then shoot with Riskrunner. If you have three Warlocks in the Strike, you can alternate with the Healing Rift and fire with fire.
Probably Bungie will be able to fix these glitches with the launch of Destiny 2.